The impact of germline mutations of the angiogenesis pathways on the therapeutic response has been extensively studied for the carcinoma population. However, such information is almost unknown for pediatric and young adult sarcoma, for which the field has seen the rapid growth the use of the anti-angiogenic therapy.
In this study, we retrospectively analyzed 79 tissue sarcoma patients less than 45 yrs old receiving anti-angiogenic therapy (apatinib). In 67 (84%) of these patients, twenty previously reported single nuclear polymorphism (SNPs) in the angiogenesis pathway were genotyped to screen for potential toxicity and predictive biomarkers.
The mean 6 mo PFS rate was 64%, with the duration of response varying from no response to more than 26 months. Multivariate analysis indicated that hand-foot reactions, hair depigmentation and spontaneously pneumothorax (SP) remain independent toxicity biomarkers for greater PFS. Interestingly, we observed a strong correlation of ITGA2 rs1126643 polymorphism vs surgical wound complications (C/C 4% vs C/T 24% vs T/T 33% , p = 0.008) as well as SP (C/C 13.8% vs C/T 36.4% vs T/T 66%), suggesting that integrin mechanisms might underle both toxicities. Moreover, VEGFR2 rs2071559 polymorphism remains the only sensitivity biomarker for mPFS (mutation vs WT, 12 mo vs 5 mo), regardless of the sarcoma subtypes. Suprisingly, such mutations were associated with the incidence of hair depigmentation (R = 0.398, p = 0.026), further supporting that hair discoloration is a mechanism-based toxicity biomarker. Moreover, significantly higher frequencies such mutations (0.53 for ITGA polymorphism, 0.59 for VEGFR2 polymorphism) were seen in our cohort than the general Han Chinese (1000G project database) suggesting a theoretical impact on the sarcomagenesis.
Our study is the first one examining the angiogenesis germline polymorphism for the younger population in bone and soft tissue cancer. VEGFR2 (rs2071559) as well as ITGA (rs1126643) might serve as pan-sarcoma biomarkers for VEGFR2-targeted therapy and warrant further validation for its biological and clinical implications.
Clinical trial identification
Legal entity responsible for the study
Ruijin Hospital, Orthopaedic Oncology Group.
Has not received any funding.
All authors have declared no conflicts of interest.